I think many of us retirees were aprehensive to pull the trigger, even if you hate your job there's still uncertainty what retired life will be.
I was 57 when I stopped working, partly do to selling our business and partly do to some health issues. I fully intended to do something else professionally but after not working for a bit I discovered I never wanted to work again, my life suddenly had become stress free. The other thing is I was pleasantly surprised that retirement was less exspensive than I anticipated, but it helps if you go into it debt free as I did.
Don't fret about giving your notice, you'll probably be smiling as you leave your bosses office! Good luck to you!